Raise warning in the sync stage if a pipeline may be impacted by a master broken incident

What does this MR do and why?

Re: Spike: create a job in the `sync` stage and can... (gitlab-org/quality/engineering-productivity/team#419 - closed)

As a first iteration, we will fail the status check job to signal that a master broken incident may be impacting this MR pipeline. We will allow the job to fail to test out the effect.

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

See https://gitlab.com/gitlab-org/gitlab/-/jobs/6238995571